It seems like FW may have wanted to just come out and SAY that he thought the Rs were involved in the death of their daughter, but my impression is that he knew that if he did, the Rs would be much more vocal in pointing a finger at HIM for the murder. The Rs were already making noise about things that "looking back on" they told LE were suspicious about the White's behavior Christmas Day. Of course, the "suspicious" things were nonsense- it was JR who ASKED that a plate of cracked crab be held out for JB. Yet he tells LE how odd he thought it was. No one in LE ever confronted JR about this either. And I'd bet NO one at the house in Atlanta was ever asked specifically about EXACTLY what words were exchanged between JR and FW.
FW was in the Boulder house the morning of the 26th, his prints were all over. He admitted moving the suitcase. He TOUCHED things related to the crime, including admitting that he picked up the tape that was on JB's mouth.
While those things may not have been enough to convict him, or even indict him, he doesn't match the touch DNA either, so it may not have gone very far.
BUT enough to destroy his life, a fact I am sure strongly pointed out to him by the R defense lawyers.
I think FW felt he really couldn't say what he felt happened. He hoped the investigation would sort it out. Boy, was he wrong...
BTW, I'd have LOVED to see LE call JR out about exactly WHO was included in his statement that "a lot of people were here at 3 in the morning." Because according to the Rs, only 4 people were in the house at 3 in the morning.. a sleeping JR, Patsy, BR and a (by then, dead) JB.